In a more recent study of Shin et al. (100) in six patients with ASD-resistant epilepsy, five patients with ASD-responsive epilepsy, and eight healthy subjects, (R)-[11C]verapamil PET and magnetic resonance (MR) imaging with cyclosporine A (P-gp inhibitor) demonstrated significant asymmetry of P-gp expression in refractory patients compared to both seizure-free patients and healthy subjects, suggesting higher P-gp expression and lower uptake of (R)-[11C]verapamil in the group of patients with refractory epilepsy. The gene discussed is PGP; the disease is epilepsy.